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Pachathundikandi SK, Tegtmeyer N, Backert S. Masking of typical TLR4 and TLR5 ligands modulates inflammation and resolution by Helicobacter pylori. Trends Microbiol 2023; 31:903-915. [PMID: 37012092 DOI: 10.1016/j.tim.2023.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/28/2023] [Accepted: 03/13/2023] [Indexed: 04/03/2023]
Abstract
Helicobacter pylori is a paradigm of chronic bacterial infection and is associated with peptic ulceration and malignancies. H. pylori uses specific masking mechanisms to avoid canonical ligands from activating Toll-like receptors (TLRs), such as lipopolysaccharide (LPS) modification and specific flagellin sequences that are not detected by TLR4 and TLR5, respectively. Thus, it was believed for a long time that H. pylori evades TLR recognition as a crucial strategy for immune escape and bacterial persistence. However, recent data indicate that multiple TLRs are activated by H. pylori and play a role in the pathology. Remarkably, H. pylori LPS, modified through changes in acylation and phosphorylation, is mainly sensed by other TLRs (TLR2 and TLR10) and induces both pro- and anti-inflammatory responses. In addition, two structural components of the cag pathogenicity island-encoded type IV secretion system (T4SS), CagL and CagY, were shown to contain TLR5-activating domains. These domains stimulate TLR5 and enhance immunity, while LPS-driven TLR10 signaling predominantly activates anti-inflammatory reactions. Here, we discuss the specific roles of these TLRs and masking mechanisms during infection. Masking of typical TLR ligands combined with evolutionary shifting to other TLRs is unique for H. pylori and has not yet been described for any other species in the bacterial kingdom. Finally, we highlight the unmasked T4SS-driven activation of TLR9 by H. pylori, which mainly triggers anti-inflammatory responses.
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Affiliation(s)
- Suneesh Kumar Pachathundikandi
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Dept. of Biology, Chair of Microbiology, Staudtstr. 5, 91058 Erlangen, Germany; Babasaheb Bhimrao Ambedkar University, Dept. of Environmental Microbiology, School of Earth and Environmental Sciences, Vidya Vihar, Raebareli Road, Lucknow 226025, India
| | - Nicole Tegtmeyer
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Dept. of Biology, Chair of Microbiology, Staudtstr. 5, 91058 Erlangen, Germany
| | - Steffen Backert
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Dept. of Biology, Chair of Microbiology, Staudtstr. 5, 91058 Erlangen, Germany.
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Cong Y, Wang Y, Yuan T, Zhang Z, Ge J, Meng Q, Li Z, Sun S. Macrophages in aseptic loosening: Characteristics, functions, and mechanisms. Front Immunol 2023; 14:1122057. [PMID: 36969165 PMCID: PMC10030580 DOI: 10.3389/fimmu.2023.1122057] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 02/13/2023] [Indexed: 03/10/2023] Open
Abstract
Aseptic loosening (AL) is the most common complication of total joint arthroplasty (TJA). Both local inflammatory response and subsequent osteolysis around the prosthesis are the fundamental causes of disease pathology. As the earliest change of cell behavior, polarizations of macrophages play an essential role in the pathogenesis of AL, including regulating inflammatory responses and related pathological bone remodeling. The direction of macrophage polarization is closely dependent on the microenvironment of the periprosthetic tissue. When the classically activated macrophages (M1) are characterized by the augmented ability to produce proinflammatory cytokines, the primary functions of alternatively activated macrophages (M2) are related to inflammatory relief and tissue repair. Yet, both M1 macrophages and M2 macrophages are involved in the occurrence and development of AL, and a comprehensive understanding of polarized behaviors and inducing factors would help in identifying specific therapies. In recent years, studies have witnessed novel discoveries regarding the role of macrophages in AL pathology, the shifts between polarized phenotype during disease progression, as well as local mediators and signaling pathways responsible for regulations in macrophages and subsequent osteoclasts (OCs). In this review, we summarize recent progress on macrophage polarization and related mechanisms during the development of AL and discuss new findings and concepts in the context of existing work.
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Affiliation(s)
- Yehao Cong
- Department of Joint Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Orthopaedic Research Laboratory, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Yi Wang
- Department of Joint Surgery, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, China
| | - Tao Yuan
- Department of Joint Surgery, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, China
| | - Zheng Zhang
- Department of Joint Surgery, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, China
| | - Jianxun Ge
- Department of Joint Surgery, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, China
| | - Qi Meng
- Department of Joint Surgery, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, China
| | - Ziqing Li
- Department of Joint Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Orthopaedic Research Laboratory, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
- *Correspondence: Ziqing Li, ; Shui Sun,
| | - Shui Sun
- Department of Joint Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Orthopaedic Research Laboratory, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
- Department of Joint Surgery, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, China
- *Correspondence: Ziqing Li, ; Shui Sun,
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Yuan J, Li X, Fang N, Li P, Zhang Z, Lin M, Hou Q. Perilla Leaf Extract (PLE) Attenuates COPD Airway Inflammation via the TLR4/Syk/PKC/NF-κB Pathway In Vivo and In Vitro. Front Pharmacol 2022; 12:763624. [PMID: 35058774 PMCID: PMC8764369 DOI: 10.3389/fphar.2021.763624] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 12/10/2021] [Indexed: 11/20/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is a complex and heterogeneous disease characterized by persistent airflow limitation but still lacking effective treatments. Perilla frutescens (L.) Britt., an important traditional medicinal plant with excellent antioxidant and anti-inflammatory properties, is widely used for the treatment of respiratory disease in China. However, its protective activity and mechanism against COPD airway inflammation have not been fully studied. Here, the anti-inflammatory effects of the PLE were investigated, and its underlying mechanisms were then elucidated. The presented results suggested a notable effect of the PLE on airway inflammation of COPD, by significantly ameliorating inflammatory cell infiltration in lung tissue, lessening leukocytes (lymphocytes, neutrophils, and macrophages) and inflammatory mediators (interleukin 4 (IL-4), IL-6, IL-17A, interferon γ (IFN-γ), and tumor necrosis factor α (TNF-α)) in the bronchoalveolar lavage fluid (BALF) of cigarette smoke (CS)/lipopolysaccharide (LPS)-induced COPD mice in vivo and inhibiting the production of inflammatory factors (nitric oxide (NO), IL-6, and TNF-α) and intracellular reactive oxygen species (ROS) in LPS-stimulated RAW264.7 cells in vitro. For further extent, PLE treatment significantly suppressed the expression and phosphorylation of TLR4, Syk, PKC, and NF-κB p65 in vivo and their mRNA in vitro. Subsequently, by co-treating with their inhibitors in vitro, its potential mechanism via TLR4/Syk/PKC/NF-κB p65 signals was disclosed. In summary, the obtained results indicated a noteworthy effective activity of the PLE on COPD inflammation, and partly, the TLR4/Syk/PKC/NF-κB p65 axis might be the potential mechanism.
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Affiliation(s)
- Jiqiao Yuan
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xuyu Li
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Nan Fang
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ping Li
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ziqian Zhang
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Mingbao Lin
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qi Hou
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Baj J, Forma A, Sitarz M, Portincasa P, Garruti G, Krasowska D, Maciejewski R. Helicobacter pylori Virulence Factors-Mechanisms of Bacterial Pathogenicity in the Gastric Microenvironment. Cells 2020; 10:E27. [PMID: 33375694 PMCID: PMC7824444 DOI: 10.3390/cells10010027] [Citation(s) in RCA: 157] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/18/2020] [Accepted: 12/22/2020] [Indexed: 12/11/2022] Open
Abstract
Gastric cancer constitutes one of the most prevalent malignancies in both sexes; it is currently the fourth major cause of cancer-related deaths worldwide. The pathogenesis of gastric cancer is associated with the interaction between genetic and environmental factors, among which infection by Helicobacter pylori (H. pylori) is of major importance. The invasion, survival, colonization, and stimulation of further inflammation within the gastric mucosa are possible due to several evasive mechanisms induced by the virulence factors that are expressed by the bacterium. The knowledge concerning the mechanisms of H. pylori pathogenicity is crucial to ameliorate eradication strategies preventing the possible induction of carcinogenesis. This review highlights the current state of knowledge and the most recent findings regarding H. pylori virulence factors and their relationship with gastric premalignant lesions and further carcinogenesis.
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Affiliation(s)
- Jacek Baj
- Department of Anatomy, Medical University of Lublin, 20-400 Lublin, Poland;
| | - Alicja Forma
- Chair and Department of Forensic Medicine, Medical University of Lublin, 20-090 Lublin, Poland;
| | - Monika Sitarz
- Department of Conservative Dentistry with Endodontics, Medical University of Lublin, 20-090 Lublin, Poland;
| | - Piero Portincasa
- Clinica Medica “Augusto Murri”, Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70124 Bari, Italy;
| | - Gabriella Garruti
- Section of Endocrinology, Department of Emergency and Organ Transplantations, University of Bari “Aldo Moro” Medical School, Piazza G. Cesare 11, 70124 Bari, Italy;
| | - Danuta Krasowska
- Department of Dermatology, Venerology and Paediatric Dermatology of Medical University of Lublin, 20-081 Lublin, Poland;
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Rossato MF, Hoffmeister C, Trevisan G, Bezerra F, Cunha TM, Ferreira J, Silva CR. Monosodium urate crystal interleukin-1β release is dependent on Toll-like receptor 4 and transient receptor potential V1 activation. Rheumatology (Oxford) 2020; 59:233-242. [PMID: 31298290 DOI: 10.1093/rheumatology/kez259] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 05/03/2019] [Indexed: 01/19/2023] Open
Abstract
OBJECTIVE The present study aimed to elucidate the mechanisms involved in MSU-induced IL-1β release in a rodent animal model of acute gout arthritis. METHODS Painful (mechanical and thermal hypersensitivity, ongoing pain and arthritis score) and inflammatory (oedema, plasma extravasation, cell infiltration and IL-1β release) parameters were assessed several hours after intra-articular injection of MSU (100 µg/articulation) in wild-type or knockout mice for Toll-like receptor 4 (TLR4), inducible nitric oxide synthase (iNOS), transient receptor potential (TRP) V1 and the IL-1 receptor (IL-1R). Also, wild-type animals were treated with clodronate, lipopolysaccharide from Rhodobacter sphaeroides (LPS-RS) (TLR4 antagonist), spleen tyrosine kinase (SYK) inhibitor (iSYK), aminoguanidine (AMG, an iNOS inhibitor) or SB366791 (TRPV1 antagonist). Nitrite/nitrate and IL-1β levels were measured on the synovial fluid of wild-type mice, 2 h after intra-articular MSU injections, or medium from macrophages stimulated for MSU (1000 μg) for 2 h. RESULTS Intra-articular MSU injection caused robust nociception and severe inflammation from 2 up to 6 h after injection, which were prevented by the pre-treatment with clodronate, LPS-RS, iSYK, AMG and SB366791, or the genetic ablation of TLR4, iNOS, TRPV1 or IL-1R. MSU also increased nitrite/nitrate and IL-1β levels in the synovial fluid, which was prevented by clodronate, LPS-RS, iSYK and AMG, but not by SB366791. Similarly, MSU-stimulated peritoneal macrophages released nitric oxide, which was prevented by LPS-RS, iSYK and AMG, but not by SB366791, and released IL-1β, which was prevented by LPS-RS, iSYK, AMG and SB366791. CONCLUSION Our data indicate that MSU may activate TLR4, SYK, iNOS and TRPV1 to induce the release of IL-1β by macrophages, triggering nociception and inflammation during acute gout attack.
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Affiliation(s)
- Mateus F Rossato
- Graduated Program in Pharmacology, Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Carin Hoffmeister
- Graduated Program in Pharmacology, Biochemistry and Molecular Biology Department, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil
| | - Gabriela Trevisan
- Graduated Program in Pharmacology, Biochemistry and Molecular Biology Department, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil
| | - Fabio Bezerra
- Graduated Program in Pharmacology, Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Thiago M Cunha
- Graduated Program in Pharmacology, Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Juliano Ferreira
- Graduated Program in Pharmacology, Pharmacology Department, Federal University of Santa Catarina (UFSC), Florianopolis, Santa Catarina, Brazil
| | - Cassia R Silva
- Graduated Program in Genetics and Biochemistry, Biotechnology Institute, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil
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Kurniawan DW, Storm G, Prakash J, Bansal R. Role of spleen tyrosine kinase in liver diseases. World J Gastroenterol 2020; 26:1005-1019. [PMID: 32205992 PMCID: PMC7081001 DOI: 10.3748/wjg.v26.i10.1005] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/14/2020] [Accepted: 02/28/2020] [Indexed: 02/06/2023] Open
Abstract
Spleen tyrosine kinase (SYK) is a non-receptor tyrosine kinase expressed in most hematopoietic cells and non-hematopoietic cells and play a crucial role in both immune and non-immune biological responses. SYK mediate diverse cellular responses via an immune-receptor tyrosine-based activation motifs (ITAMs)-dependent signalling pathways, ITAMs-independent and ITAMs-semi-dependent signalling pathways. In liver, SYK expression has been observed in parenchymal (hepatocytes) and non-parenchymal cells (hepatic stellate cells and Kupffer cells), and found to be positively correlated with the disease severity. The implication of SYK pathway has been reported in different liver diseases including liver fibrosis, viral hepatitis, alcoholic liver disease, non-alcoholic steatohepatitis and hepatocellular carcinoma. Antagonism of SYK pathway using kinase inhibitors have shown to attenuate the progression of liver diseases thereby suggesting SYK as a highly promising therapeutic target. This review summarizes the current understanding of SYK and its therapeutic implication in liver diseases.
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Affiliation(s)
- Dhadhang Wahyu Kurniawan
- Department of Biomaterials Science and Technology, Faculty of Science and Technology, Technical Medical Centre, University of Twente, Enschede 7500, the Netherlands
- Department of Pharmacy, Universitas Jenderal Soedirman, Purwokerto 53132, Indonesia
| | - Gert Storm
- Department of Biomaterials Science and Technology, Faculty of Science and Technology, Technical Medical Centre, University of Twente, Enschede 7500, the Netherlands
- Department of Pharmaceutics, University of Utrecht, Utrecht 3454, the Netherlands
| | - Jai Prakash
- Department of Biomaterials Science and Technology, Faculty of Science and Technology, Technical Medical Centre, University of Twente, Enschede 7500, the Netherlands
| | - Ruchi Bansal
- Department of Biomaterials Science and Technology, Faculty of Science and Technology, Technical Medical Centre, University of Twente, Enschede 7500, the Netherlands
- Department of Pharmacokinetics, Toxicology and Targeting, Groningen Research Institute of Pharmacy, University of Groningen, Enschede 7500, the Netherlands
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Jung HJ, Kang JH, Pak S, Lee K, Seong JK, Oh SH. Detrimental Role of Nerve Injury-Induced Protein 1 in Myeloid Cells under Intestinal Inflammatory Conditions. Int J Mol Sci 2020; 21:ijms21020614. [PMID: 31963519 PMCID: PMC7013940 DOI: 10.3390/ijms21020614] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 01/15/2020] [Accepted: 01/16/2020] [Indexed: 12/24/2022] Open
Abstract
Nerve injury-induced protein 1 (Ninjurin1, Ninj1) is a cell-surface adhesion molecule that regulates cell migration and attachment. This study demonstrates the increase in Ninj1 protein expression during development of intestinal inflammation. Ninj1-deficient mice exhibited significantly attenuated bodyweight loss, shortening of colon length, intestinal inflammation, and lesser pathological lesions than wild-type mice. Although more severe inflammation and serious lesions are observed in wild-type mice than Ninj1-deficient mice, there were no changes in the numbers of infiltrating macrophages in the inflamed tissues obtained from WT and Ninj1-deficient mice. Ninj1 expression results in activation of macrophages, and these activated macrophages secrete more cytokines and chemokines than Ninj1-deficient macrophages. Moreover, mice with conditional deletion of Ninj1 in myeloid cells (Ninj1fl/fl; Lyz-Cre+) alleviated experimental colitis compared with wild-type mice. In summary, we propose that the Ninj1 in myeloid cells play a pivotal function in intestinal inflammatory conditions.
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Affiliation(s)
- Hyun Jin Jung
- Interdisciplinary Program in Cancer Biology, College of Medicine, Seoul National University, Seoul 03080, Korea;
- Korea Mouse Phenotyping Center, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Ju-Hee Kang
- College of Pharmacy, Gachon University, Incheon 21936, Korea
| | - Seongwon Pak
- Department of Biomedical Science, Hallym University, Chuncheon 24252, Korea
| | - Keunwook Lee
- Department of Biomedical Science, Hallym University, Chuncheon 24252, Korea
| | - Je Kyung Seong
- Interdisciplinary Program in Cancer Biology, College of Medicine, Seoul National University, Seoul 03080, Korea;
- Korea Mouse Phenotyping Center, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
- Laboratory of Developmental Biology and Genomics, Research Institute of Veterinary Science, BK21 Plus Program for Veterinary Science, Seoul National University, Seoul 08826, Korea
- Correspondence: (J.K.S.); (S.H.O.)
| | - Seung Hyun Oh
- College of Pharmacy, Gachon University, Incheon 21936, Korea
- Correspondence: (J.K.S.); (S.H.O.)
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Chichirau BE, Diechler S, Posselt G, Wessler S. Tyrosine Kinases in Helicobacter pylori Infections and Gastric Cancer. Toxins (Basel) 2019; 11:toxins11100591. [PMID: 31614680 PMCID: PMC6832112 DOI: 10.3390/toxins11100591] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/02/2019] [Accepted: 10/09/2019] [Indexed: 12/11/2022] Open
Abstract
Helicobacter pylori (H. pylori) has been identified as a leading cause of gastric cancer, which is one of the most frequent and malignant types of tumor. It is characterized by its rapid progression, distant metastases, and resistance to conventional chemotherapy. A number of receptor tyrosine kinases and non-receptor tyrosine kinases have been implicated in H. pylori-mediated pathogenesis and tumorigenesis. In this review, recent findings of deregulated EGFR, c-Met, JAK, FAK, Src, and c-Abl and their functions in H. pylori pathogenesis are summarized.
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Affiliation(s)
- Bianca E Chichirau
- Department of Biosciences, Paris-Lodron University of Salzburg, 5020 Salzburg, Austria.
| | - Sebastian Diechler
- Department of Biosciences, Paris-Lodron University of Salzburg, 5020 Salzburg, Austria.
| | - Gernot Posselt
- Department of Biosciences, Paris-Lodron University of Salzburg, 5020 Salzburg, Austria.
| | - Silja Wessler
- Cancer Cluster Salzburg, Department of Biosciences, Paris-Lodron University of Salzburg, 5020 Salzburg, Austria.
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Slomiany BL, Slomiany A. Syk: a new target for attenuation of Helicobacter pylori-induced gastric mucosal inflammatory responses. Inflammopharmacology 2019; 27:203-211. [PMID: 30820719 DOI: 10.1007/s10787-019-00577-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 02/19/2019] [Indexed: 02/07/2023]
Abstract
The magnitude of gastric mucosal inflammatory response to H. pylori relies primarily on the extent of its key endotoxin, LPS, engagement of Toll-like receptor-4 (TLR4) and the initiation of signal transduction events converging on mitogen-activated protein kinase (MAPK) and IκB complex (IKK) cascades. These cascades, in turn, exert their control over the assembly of transcription factors, NFκB and AP1, implicated in the induction of the expression of iNOS and COX-2 proinflammatory genes. The LPS-induced TLR4 activation and the ensuing phosphorylation of its intracellular tyrosine domain by Src-family kinases not only leads to recruitment to the cytoplasmic domain of TLR4 of adaptor molecules directly involved in propagation of the signaling cascades converging on MAPK and IKK, but also provides a propitious docking site for a non-receptor tyrosine kinase, spleen tyrosine kinase (Syk), the activation of which apparently leads to upregulation in the expression of proinflammatory genes. Here, we review the pathways engaged by H. pylori in the recruitment and interaction of Syk with TLR4 in gastric mucosa, and discuss the cascades involved in Syk-mediated amplification in proinflammatory signaling. We focus, moreover, on the potential role of drugs targeting Syk and TLR4 in the treatment of H. pylori-related gastric disease.
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Affiliation(s)
- Bronislaw L Slomiany
- Research Center, C855, Rutgers School of Dental Medicine, Rutgers, The State University of New Jersey, 110 Bergen Street, PO Box 1709, Newark, NJ, 07103-2400, USA.
| | - Amalia Slomiany
- Research Center, C855, Rutgers School of Dental Medicine, Rutgers, The State University of New Jersey, 110 Bergen Street, PO Box 1709, Newark, NJ, 07103-2400, USA
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